What is the best practice for creating a yes/no
i.e. Boolean
field when converting from an access database
or in general?
This question is related to
sql-server
boolean
sqldatatypes
The BIT
datatype is generally used to store boolean
values (0
for false
, 1
for true
).
You can use the BIT
field.
For adding a BIT column to an existing table, the SQL command would look like:
ALTER TABLE table_name ADD yes_no BIT
If you want to create a new table, you could do: CREATE TABLE table_name (yes_no BIT)
.
You can use the data type bit
Values inserted which are greater than 0 will be stored as '1'
Values inserted which are less than 0 will be stored as '1'
Values inserted as '0' will be stored as '0'
This holds true for MS SQL Server 2012 Express
bit
is the most suitable option. Otherwise I once used int
for that purpose. 1
for true
& 0
for false
.
bit
will be the simplest and also takes up the least space. Not very verbose compared to "Y/N" but I am fine with it.
Sample usage while creating a table:
[ColumnName] BIT NULL DEFAULT 0
You can use the bit
column type.
In SQL Server Management Studio of Any Version, Use
BIT
as Data Type
which will provide you with True
or False
Value options. in case you want to use Only 1
or 0
then you can use this method:
CREATE TABLE SampleBit(
bar int NOT NULL CONSTRAINT CK_foo_bar CHECK (bar IN (-1, 0, 1))
)
But I will strictly advise BIT
as The BEST Option. Hope fully it's help someone.
There are already answers saying use of Bit. I will add more to these answers.
You should use bit for representing Boolean values.
Remarks from MSDN article.
Bit can take a value of 1, 0, or NULL.
The SQL Server Database Engine optimizes storage of bit columns. If there are 8 or less bit columns in a table, the columns are stored as 1 byte. If there are from 9 up to 16 bit columns, the columns are stored as 2 bytes, and so on.
The string values TRUE and FALSE can be converted to bit values: TRUE is converted to 1 and FALSE is converted to 0.
Converting to bit promotes any nonzero value to 1.
NOT NULL
As Bit have values 1, 0 and NULL. See truth table for this. So plan values accordingly. It might add confusion by allowing NULL value for bit data type.
You can use the BIT
field
To create new table:
CREATE TABLE Tb_Table1
(
ID INT,
BitColumn BIT DEFAULT 1
)
Adding Column in existing Table:
ALTER TABLE Tb_Table1 ADD BitColumn BIT DEFAULT 1
To Insert record:
INSERT Tb_Table1 VALUES(11,0)
Source: Stackoverflow.com